The invention pertains to the fields of chemistry and mechanical engineering and relates to glass fiber surfaces which are modified without sizing material and silane, which glass fiber surfaces can be further processed into and used as composite materials, for example as reinforcing fiber materials for plastics, and to a method for producing the modified glass fiber surfaces. The object of the present invention is to provide glass fiber surfaces modified without sizing materials and silane, which glass fiber surfaces exhibit improved properties overall and for a further processing into composite materials, and furthermore to provide a simple and cost-effective method for producing glass fiber surfaces modified in such a manner. The object is attained with glass fiber surfaces modified without sizing material and silane, which glass fiber surfaces are at least partially covered at least with a hydrolysis-stable and/or solvolysis-stable cationic polyelectrolyte and/or hydrolysis-stable and/or solvolysis-stable cationic polyelectrolyte mixture and/or with a hydrolysis-stable and/or solvolysis-stable polyelectrolyte complex and coupled to the glass fiber surface via a (polyelectrolyte) complex formation process by means of ionic bonding, with the polyelectrolyte complex A thereby being formed.

Glass compositions and glass fibers having low dielectric constants and low dissipation factors that may be suitable for use in electronic applications and articles are disclosed. The glass fibers and compositions of the present invention may include between 45.0 to 58.0 weight percent SiO.sub.2; greater than 18.0 weight percent B.sub.2O.sub.3 and no more than 26.0 weight percent B.sub.2O.sub.3; greater than 16.0 weight percent Al.sub.2O.sub.3 and no more than 23.0 weight percent Al.sub.2O.sub.3; between 0.25 to 12.0 weight percent P.sub.2O.sub.5; greater than 0.25 weight percent CaO and less than 5.00 weight percent CaO; less than 4.50 weight percent MgO; greater than 0.25 weight percent CaO+MgO and less than 5.00 weight percent CaO+MgO; less than 0.80 weight percent Fe.sub.2O.sub.3; and less than 0.50 weight percent TiO.sub.2. Further, the glass composition has a glass viscosity of 1000 poise at a temperature greater than 1350 degrees Celsius.

Glass compositions and glass fibers having low dielectric constants and low dissipation factors that may be suitable for use in electronic applications and articles are disclosed. The glass fibers and compositions of the present invention may include between 45.0 to 58.0 weight percent SiO.sub.2; greater than 18.0 weight percent B.sub.2O.sub.3 and no more than 26.0 weight percent B.sub.2O.sub.3; greater than 16.0 weight percent AI.sub.2O.sub.3 and no more than 23.0 weight percent AI.sub.2O.sub.3; between 0.25 to 12.0 weight percent P.sub.2O.sub.5; greater than 0.25 weight percent CaO and less than 5.00 weight percent CaO; less than 4.50 weight percent MgO; greater than 0.25 weight percent CaO+MgO and less than 5.00 weight percent CaO+MgO; less than 0.80 weight percent Fe.sub.2O.sub.3; and less than 0.50 weight percent TiO.sub.2. Further, the glass composition has a glass viscosity of 1000 poise at a temperature greater than 1350 degrees Celsius.